Generally speaking, the house sales contract must be signed by the person; in special circumstances, the trustee can sign the contract with his or her ID card, the principal’s handwritten power of attorney (or notarial certificate) and his or her identity document. . Things to note when signing a house purchase contract: 1. The basic "five certificates" are complete. Be sure to check whether the developer has a commercial housing pre-sale license. With a pre-sale license, the developer usually also has a real estate development license, a state-owned land use certificate, a construction project development license, and a project planning license*** Five certificates. This is the key to whether you can get a real estate certificate when buying a house. 2. Use standardized contract text. Be sure to refer to the "It is best to adopt and do not modify it at will" and fill in the text carefully in accordance with the terms listed in the text to understand the specific contents. Don't just sign the "Order Agreement" decided by the developer and pay a deposit. 3. Relevant certification documents are valid. If you are buying a house off-plan (a house under construction, unfinished construction, or a house that cannot be delivered for use), you must check whether the developer has a pre-sale license and confirm that the house you are buying is within the pre-sale range; if you are buying an existing house, you must check the developer Do you have the real estate certificate for the house (obtained after the pre-sale permit, that is, the house is realized from the off-plan house) and the "New Residential Delivery Permit". 4. In addition, the conditions and time limit must be agreed upon when buying a house off-plan. The so-called house delivery has two meanings: one is the physical delivery of the right to use the house; the other is the transfer of house ownership, which is the transfer of property rights. Both the physical delivery and the transfer of property rights should be clearly agreed upon in the pre-sale contract, and the delivery of a house without a "New Residential Delivery and Use Permit" cannot be accepted. 5. Clarify the specific time and liability for breach of contract. For off-plan properties, it is common for the property to be delayed due to insufficient funds, and some may even fail to deliver the property. If it is not a standardized "text", the developer will definitely make a fuss about the contract, which will be extremely detrimental to the home buyers. 6. Check the quality of the house. When signing a contract, you should read and check the contents of the "Residential Instruction Manual" and the "Commercial Housing Quality Guarantee", and use the "Commercial Housing Quality Guarantee" as an attachment to the contract to check whether the developer is responsible for quality problems. 7. Clarify property management matters. A bad property management company will definitely make you feel uncomfortable forever. Therefore, you need to learn more about the specifics of the property management company, as well as the property management scope and charging standards agreed by both parties. 8. Key points: Agreement on liability for breach of contract. For off-plan houses or even existing houses, it may be different from the developer's description. At this time, it should be clear what the developer's responsibilities should be in case of breach of contract or inconsistency with the description.